package com.sunny.rpc.base.core;

import com.sunny.springboot2.core.exception.CustomException;
import com.sunny.springboot2.enums.ExceptionEnums;
import org.apache.commons.lang3.StringUtils;

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * Rpc简单实现
 *
 * @author Sunny
 * @date 2019/6/7 13:40
 */
public class RpcFramework {

    /**
     * 暴露服务
     *
     * @param service 服务实现
     * @param port 服务端口
     * @author sunny
     * @date 2019/6/7 14:08
     * @return void
     */
    public static void export(final Object service, final int port) throws Exception {
        if (service == null) {
            throw new CustomException(ExceptionEnums.SERVER_NOT_EXiSTS_EXCEPTION);
        }
        if (port <= 0 || port > 65535) {
            throw new CustomException(ExceptionEnums.PORT_RANGE_EXCEPTION);
        }
        System.out.println("Export service: " + service.getClass().getName() + " on port: " + port);

        ServerSocket server = new ServerSocket(port);
        while (true) {
            try {
                final Socket socket = server.accept();
                new Thread(() -> {
                    try {
                        try {
                            ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
                            try {
                                String methodName = input.readUTF();
                                Class<?>[] paramTypes = (Class<?>[]) input.readObject();
                                Object[] arguments = (Object[]) input.readObject();

                                ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
                                try {
                                    Method method = service.getClass().getMethod(methodName, paramTypes);
                                    Object result = method.invoke(service, arguments);
                                    output.writeObject(result);
                                } catch (Throwable t) {
                                    output.writeObject(t);
                                } finally {
                                    output.close();
                                }
                            } finally {
                                input.close();
                            }
                        } finally {
                            socket.close();
                        }
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }).start();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 引用服务
     *
     * @param interfaceClass 接口类型
     * @param host 服务主机ip
     * @param port 服务主机端口
     * @author sunny
     * @date 2019/6/7 14:22
     * @return T 远程服务
     */
    public static <T> T refer(final Class<T> interfaceClass, final String host, final int port) throws Exception {
        if (interfaceClass == null) {
            throw new IllegalArgumentException("Interface class is null");
        }
        if (!interfaceClass.isInterface()) {
            throw new IllegalArgumentException("the method " + interfaceClass.getName() + "must be interface class");
        }
        if (StringUtils.isBlank(host)) {
            throw new IllegalArgumentException("host is null");
        }
        if (port <= 0 || port > 65535) {
            throw new CustomException(ExceptionEnums.PORT_RANGE_EXCEPTION);
        }
        System.out.println("Get remote service " + interfaceClass.getName() + " from server " + host + ":" + port);
        return (T) Proxy.newProxyInstance(interfaceClass.getClassLoader(), new Class[]{interfaceClass}, (proxy, method, args) -> {
            Socket socket = new Socket(host, port);
            try {
                ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());

                try {
                    output.writeUTF(method.getName());
                    output.writeObject(method.getParameterTypes());
                    output.writeObject(args);
                    ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
                    try {
                        Object result = input.readObject();
                        if (result instanceof Throwable) {
                            throw (Throwable) result;
                        }
                        return result;
                    } finally {
                        input.close();
                    }
                } finally {
                    output.close();
                }
            } finally {
                socket.close();
            }
        });
    }
}
